Mobile communication technology has progressed rapidly in recent years. Consumers are increasingly using mobile communication devices such as cellular phones, web-enabled cellular telephones, Personal Digital Assistants (PDAs), hand-held computers, laptops, tablets and other devices capable of communication over public or private communication networks. The expansion of cellular networks and technological advancements in mobile communications have resulted in more consumers using mobile communications devices. This increased demand for communication devices drives improvements in the manufacturing processes, power consumption, reception, fabrication, and miniaturization of audio components incorporated in the mobile communication devices. Competitive pressures among suppliers of mobile communication devices increase the demand for smaller, less expensive, and better performing miniature capacitor microphones.
Generally speaking, a variety of conventional electret condenser microphones (“ECMs”) have been used for communication devices. A prior art ECM comprises a dust guard, a housing with an acoustic port, a vibratory diaphragm, a spacer, an insulating body, a backplate assembly, a conductive ring, and a printed circuit board (“PCB”). The diaphragm assembly and the backplate assembly constitute a variable capacitor portion responsive to sound pressure level changes coupled through the acoustic port corresponding to the thickness of the spacer.
As the size of the ECM is reduced, limited space is available to accommodate the insulating body and the conductive ring resulting in increased interference between the capacitor portion and the PCB. Apart from the pursuit of miniaturization, repetitive shocks and vibration may create a deleterious effect on acoustic performance of ECMs over time.